how can I show a texture over my bump texture?
The node setup you have shown looks like it should work fine.  I believe your problem is that you are multiplying the bump map by 0.000, effectively disabling it.  Try increasing the value of the Multiply node.

If the Multiply node is just supposed to control the strength, you don't need it at all, you can just adjust the Strength slider on the Bump Map node.  You can also delete the Invert Color node and use the Invert checkbox on the Bump Map node.

Just select the Invert node and the Math Multiply node and hit Ctrl+X to delete them and keep the other nodes connected.  Then adjust the Strength and select Invert on the Bump Map node itself.